3 Local Anesthetics for Spinal Anesthesia in Primary Total Hip Arthroplasty
3 Local Anesthetics for Spinal Anesthesia in Primary Total Hip Arthroplasty
Spinal anesthesia is commonly utilized for hip replacement surgery. Different medications
 used for spinal anesthesia work for different lengths of time. This study will compare three
 different spinal anesthesia medications in patients having hip replacement surgery to see if
 patients are able to get out of bed and walk earlier after surgery with one medication versus
 the others.
Total hip replacement is often performed under spinal anesthesia, which is the standard at
 Thomas Jefferson University Hospital (TJUH) and Rothman Orthopedic Specialty Hospital (ROSH)
 for patients without contraindications. Spinal anesthesia involves injecting a numbing
 medicine (local anesthetic) into the cerebrospinal fluid that bathes the spinal cord through
 a space between two bones in the back. This causes temporary numbness of the legs and hips
 and allows surgery to take place without patients feeling pain during surgery. Different
 local anesthetics can be used for spinal anesthesia and each works for a different duration
 of time. Another factor that affects how spinal anesthesia medications work is the baricity
 of the medication, which refers to how dense it is compared to cerebrospinal fluid (CSF).
 Medications that are less dense than CSF are hypobaric, those with same density are isobaric,
 and those with greater density are hyperbaric. For clinical purposes, this really only comes
 into play when positioning the patient immediately after spinal placement as patient position
 has different effects on the dermatomal level attained depending on baricity of the local
 anesthetic. Bupivacaine is a long-acting local anesthetic that has been used for several
 decades for total hip replacement. It is available in both hyperbaric form (with dextrose
 added) and isobaric form (with no dextrose added). Mepivacaine is another local anesthetic
 that has a shorter duration of action and is also used for spinal anesthesia in total hip
 replacement at many centers. All three drugs are used routinely at different centers in the
 United States. Despite the differences in duration that have been described from
 pharmacokinetic studies, a randomized, controlled study comparing the three drugs in terms of
 important outcomes, such as the ability to walk after surgery, has not been published yet.
 Therefore, the investigators want to compare the three local anesthetics in a randomized,
 controlled fashion to see if more patients are able to walk sooner after receiving
 mepivacaine spinal anesthesia than either form of bupivacaine spinal anesthesia.

 Patients who are eligible will be called the night prior to surgery and the study will be
 explained over the phone. Patients who express interest will be recruited on the day of their
 scheduled surgery in the short-procedure unit. Patients will be given consent forms and time
 to read them and ask questions.

 Preoperative Management All patients without contraindications or allergies will receive oral
 gabapentin and acetaminophen in the short procedure unit prior to surgery per routine
 practice.

 Intraoperative Management The targeted spinal dermatome level to achieve will be T10
 (umbilicus). For isobaric drugs, patients will sit after spinal placement for 3-5 minutes to
 achieve this level. For hyperbaric bupivacaine, patients will be immediately placed supine
 and in Trendelenberg position for 3-5 minutes to achieve adequate level and confirmed with
 sensory pinprick testing, which will be performed every 2 minutes beginning at spinal
 placement time. After spinal is placed, sedation will be titrated at the discretion of the
 anesthesia team to achieve the American Society of Anesthesiology's definition of moderate
 sedation (purposeful response to verbal or tactile stimulation, spontaneous ventilation, and
 no airway intervention needed) using propofol. All patients will receive tranexamic acid
 unless contraindicated (10 mg/kg bolus), as well as multimodal analgesia with a non-steroidal
 anti-inflammatory drug (NSAID) and dexamethasone 4 mg IV per routine practice.

 Postoperative Management

 Sensory and motor assessments will take place every 30 minutes from PACU arrival time until
 motor strength is 5/5 in both lower extremities in hip flexion, knee extension, and toe
 dorsiflexion or the patient's motor function returns to baseline. The time of return of motor
 function will be documented. Physical therapists will visit the patient between 3 and 3.5
 hours after spinal placement to assess for ability to ambulate and perform Tinnetti test,
 which assesses ambulation and gait and gives a score of 0 through 28 (see attached). Urinary
 retention will be assessed through asking the following on postoperative day 1:

 1. At what time did the participant first urinate?

 2. Did participant require a Foley catheter or straight catheter to drain urine from his or
 her bladder?

 These questions will be asked along with the following about TNS (transient neurological
 symptoms):

 1. Does the participant have any pain in his or her lower back that goes into his or her
 buttocks and/or down his or her thigh that was not there before surgery?

 2. If yes, how would the participant rate that specific pain from 0 (no pain) to 10 (worst
 pain imaginable).

 3. How would the participant rate his/her overall pain (0 to 10 scale)?

 4. How satisfied is the participant with his/her anesthesia experience (0 to 10 scale where
 0 is very dissatisfied and 10 is very satisfied)?

 TNS will be defined as the new onset (within 24 hours of surgery) of back pain that radiates
 into the buttocks, thighs, hips, or distally. Localized back pain will not be included.

 Urinary retention will be defined by inability to urinate within 8 hours, a report of
 distended or painful bladder occurring on postoperative days 0 or 1, either by patient report
 or on assessment by nursing, or the use of a Foley catheter or straight catheter.

 Post-discharge phone calls

 The following will be asked to patients via phone calls after discharge at 24 and 48 hours
 after surgery if not still in the hospital (will be asked in-person otherwise):

 1. Does the participant have any back pain that was not present before surgery that goes
 into his/her buttocks, thighs, hips, or lower leg?

 2. If yes, how would the participant rate that specific pain from 0 (no pain) to 10 (worst
 pain imaginable).

 3. How would the participant rate his/her overall pain (0 to 10 scale)?

 4. How satisfied is the participant with his/her anesthesia experience (0 to 10 scale where
 0 is very dissatisfied and 10 is very satisfied)?

 Post-discharge data collection Readmissions within 90 days will be recorded for all patients
 including the reason for readmission.

 General Operating Procedures Patients who agree to participate will then be randomized by a
 computer-generated sequence to one of the three study groups. The anesthesiologist and
 certified registered nurse anesthetist or resident performing the spinal will be aware of
 group allocation and will perform spinal anesthesia according to standard operating
 procedures with the assigned local anesthetic. Intraoperative sedation will be with propofol
 or dexmedetomidine, at the discretion of the anesthesia team. Patients will remain blinded
 and surgeons and those performing postoperative assessments will remain blinded as well. As
 all study drugs are standard spinal anesthesia drugs and readily available, the anesthesia
 team caring for the patient will be informed of group allocation and the appropriate drug
 will be selected. These doses of hyperbaric and isobaric bupivacaine are considered "low
 dose" and are lower than those routinely used at TJUH and ROSH. However, existing evidence
 shows that low-dose bupivacaine for spinal anesthesia provides adequate anesthesia time for a
 total joint replacement. Dosing will be as follows: isobaric bupivacaine 12.5 mg (2.5 cc of
 0.5%) for < 74" height and 15 mg (3 cc) for > or = 74" height; hyperbaric bupivacaine 10.25
 mg (1.5 cc 0.75%) for < 74" height and 13.125 mg (1.75 cc) for > or = 74" height; and
 isobaric mepivacaine 52.5 mg (3.5 cc of 1.5%) for < 74" height and 60 mg (4 cc) for > or =
 74" height. Patients with BMI of 35 or greater will also be given the higher dose of each of
 the 3 medications listed above.

 Intraoperative variables that will be measured include: hypotension (defined as a decrease in
 baseline blood pressure of 20% or greater), surgeon rating of intraoperative muscle tension
 (0, 1, 2, or 3 where 0 is the most relaxed and 3 is the tightest), and conversion to general
 anesthesia.

 Postoperative variables that will be measured include: ambulation at 3-3.5 hours (primary
 endpoint), time to ambulation, attempts needed to ambulate, episodes of orthostatic
 hypotension while trying to ambulate, urinary retention, opioid consumption, pain, incidence
 of transient neurological symptoms up to 48 hours postoperatively, discharge readiness, and
 length of stay.

 Post-discharge phone calls

 The following will be asked to patients via phone calls after discharge on postoperative days
 1 and 2 after surgery if not still in the hospital (will be asked in-person otherwise):

 1. Does the participant have any pain in his/her lower back that goes into his/her buttocks
 and/or down his/her thigh that was not there before surgery?

 2. If yes, how would the participant rate that specific pain from 0 (no pain) to 10 (worst
 pain imaginable).

 3. How would the participant rate his/her overall pain (0 to 10 scale)?

 4. How satisfied is the participant with his/her anesthesia experience (0 to 10 scale where
 0 is very dissatisfied and 10 is very satisfied)?
Inclusion Criteria:

 -  undergoing elective primary hip replacement surgery

 -  American Society of Anesthesiologists physical status 1-3

 Exclusion Criteria:

 -  hip fracture

 -  contraindication to spinal anesthesia (refusal, coagulopathy or recent use of
 anticoagulant medication that prevents spinal anesthesia, local or systemic infection)

 -  any other reason deemed significant by attending anesthesiologist

 -  any patient requiring a wheelchair for ambulation or who cannot walk 25 feet with or
 without an assist device at time of surgery

 -  presence of neuropathy in posterior thighs or buttocks

 -  use of greater than the equivalent of morphine 25 mg IV (oxycodone 30 mg PO) daily

 -  any patient deemed a poor candidate for spinal anesthesia as determined by the
 attending anesthesiologist