Coccygectomy

Surgical removal of the coccyx is the treatment for coccygodynia (defined as pain in the region of the coccyx) in cases where conservative treatment has failed.[1, 2, 3, 4, 5, 6, 7, 8] The initial treatment for coccygodynia (coccydynia) consists of rest, anti-inflammatory medications, use of a cushion, appropriate physiotherapy, and corticosteroid injection. Surgical excision is considered as a last resort for coccygodynia.[9]

The surgical procedure of coccygectomy is described in many textbooks of orthopedic and spinal surgery. Several studies have shown good to excellent outcomes in pain relief after coccygectomy. The procedure is performed as either a partial or a complete coccygectomy[10] ; however, a few studies found that partial coccygectomy has a higher incidence of surgical failure as compared with total coccygectomy.[11, 12] This procedure is not very commonly performed but can be efficiently conducted by orthopedic or spinal surgeons who have experience with it.

The etiology of coccygodynia is still not fully understood. However, the causes of coccygodynia and the indications for coccygectomy can be divided into two broad categories: local causes and factors from other regions.[13]

Local causes include the following:

• Trauma ^[14]  (fracture, fracture dislocations, and childbirth)
• Congenital
• Tumors
• Degenerative
• Psychosomatic
• Unknown

Referring pain from the adjacent structures can also mimic coccygodynia. These factors should be ruled out before surgery is planned. Factors from other regions include the following:

• Lumbosacral injuries
• Episacral sarcoma
• Lower lumbar  spinal stenosis
• Disk herniation or painful degenerated disk
• Pain from the sacrococcygeal joint

Contraindications for coccygectomy include the following:

• Absence of organic pathology
• Significant improvement with conservative treatment
• Infection in local region

Anatomy

The coccyx is a dynamic and mobile structure as a consequence of its muscle attachments. It is more prominent in females than in males, a difference that has been suggested as a possible explanation for why coccygodynia is more common in females.[15] A clear understanding of the anatomy of the coccygeal region is important because the coccyx serves as an attachment for many important muscles and ligaments within the region. (See the image below.)

Surgeons and patients should be mindful of the importance of these attachments when considering coccygectomy. For example, the levator ani and other pelvic floor muscles are attached anteriorly to the coccyx and prevent the sagging of pelvic contents. Attached to the coccyx is the sphincter ani externus, which is responsible for bowel continence (some authors have reported fecal incontinence occurring as a result of damage to this muscle during coccygectomy). The coccyx is attached superiorly to the sacrum by anterior and posterior coccygeal ligaments. The transverse process of the coccyx provides attachment to the lateral sacrococcygeal ligaments.

In order to assess the stability of the coccyx, anteroposterior (AP) and lateral radiographs are taken. Plain radiographs may reveal fractures, dislocations, osteophytes, and abnormal sacrococcygeal curvature. However, whether the radiologic findings can be a definite pointer to indicate surgery remains undetermined.

Dynamic radiographs are usually taken to assess the hypermobility of the sacrococcygeal region. The first radiograph is taken when the patient is standing for at least 10 minutes in order to get the coccyx in a neutral position. The patient is then asked to sit with the back straight and the thighs horizontal. Next, he or she is asked to bend backwards until pain is reproduced, at which point a second radiograph is taken. Posterior subluxation is observed when a reduction in standing position occurs. Hypermobility of the coccyx is described as flexion of more than 25º on lateral radiographs.[16]

The intercoccygeal angle (see the image below) is the angle between the midline of the first coccygeal segment and the last (fourth) coccygeal segment. This is the objective measurement of forward angulation of the coccyx. In comparisons of the intercoccygeal angles in traumatic and idiopathic coccygodynia,[17]  it was found that the intercoccygeal angle was a useful radiologic measurement that could accurately assess the increased angular deformity of the coccyx; it was also found that the intercoccygeal angle was greater in idiopathic cases than in traumatic cases and could be a potential cause of coccygodynia (coccydynia).

Magnetic resonance imaging (MRI) of the lumbosacral area should be performed to rule out spinal canal, disk, or spinal cord pathology. Also, assessment of the surrounding sacrococcygeal region should be made to exclude rare but sinister pathologic conditions (eg, neoplasm).

Before being listed for coccygectomy, each patient must have failed medical therapy and nonsurgical treatment.[18, 19]  This includes the failure of manipulation under anesthetic (MUA) and at least two attempts at local anesthetic and steroid infiltration.

Usually, a low-residue diet is started 5 days before surgery, and a Fleet enema is given 24 hours before or on the day of the procedure. Some surgeons start the low-residue diet just 1 day before surgery. An increased risk of wound infection after coccygectomy has been reported; therefore, preoperative antibiotics are given after induction of anesthesia. Anecdotally, this is due to the anatomic region where the surgery is performed.

The patient is placed in a prone position on bolsters, and the operating table is flexed at the patient’s waist. The buttocks are separated by a hard tape to afford proper exposure of the area.

Two different incisions for coccygectomy have been described by surgeons; some prefer a median longitudinal incision starting above the sacrococcygeal joint and extending down to the coccyx (see the image below). Care should be taken not to extend the incision near perianal skin. The incision is deepened through the fascia and gluteus muscles until the bone is felt. With blunt dissection, the tip of the coccyx is located.

After the posterior surface of bone is exposed, the intervertebral disk between the sacrum and the coccyx is excised with the scalpel. The coccygeal vessels on each side are ligated or cauterized. The anococcygeal ligament is incised, and the tip of the coccyx is elevated. The coccygeus and the ileococcygeus are dissected through muscle attachments and incised carefully in such a way as to protect the rectum. All segments and layers of the coccyx, including the periosteum, are excised.

Some surgeons prefer to create a subperiosteal plane on both sides of the tip by means of sharp dissection and to leave the ligamentous and muscular attachments behind, along with the periosteum. Periosteum preservation and closure have been shown to result in a low risk of postoperative infection.

Because the coccyx lies close to the rectum, care must be taken in excising it. Gardener described a technique for mobilizing the rectum and dense fascia deep to the sacrococcygeal joint that has the advantages of protecting the rectum, reducing the risk of infection, and leading to more rapid healing.[20]

After the coccyx is removed (see the image below), the distal prominent end of the sacrum is beveled. The dead space is obliterated by drawing the cut ends of aponeurotic tissues in the midline and applying two to four mattress stitches with absorbable sutures. The subcutaneous tissue and skin are closed in layers. Usually, a small drain is placed if the dead space is left, and a small dressing is applied.

Minimally invasive approaches to coccygectomy have also been described.[21, 22]

After the procedure, patients are usually continued on oral antibiotics for 4-6 days. Some authorities recommend two or three more intravenous doses postoperatively.[23]

Patients are discharged from hospital within 3-5 days, provided that there are no immediate complications. Sutures are removed as appropriate in 2 weeks. Dressings are changed every 3 days. Patients should be educated accordingly; often, improvement in symptoms after coccygectomy is appreciated only after a period of several months. Patients are followed for a period of 12-36 months to assess clinical and functional outcome.

The most common complication of coccygectomy is postoperative infection. The literature has indicated an infection rate as high as 30%.

Rectal injury can occur as a result if the dissection plane strays from the subperiosteal region.

Some authors have also documented fecal incontinence following the procedure as a result of damage to the sphincter ani externus.

The ganglion impar is located just anterior to the coccyx (the last ganglion of the paravertebral sympathetic nervous system). Therefore, a potential risk of damage to the sympathetic nerve supply exists during coccygectomy.