Tail injuries are common in cats, and those involving traction and avulsion, colloquially called "tail pull" injuries can occur secondary to accidents with household or garage doors, fences, and automobiles. In these situations, the tail is forcefully pulled away from the body, and there can be separation and/or displacement of sacrocaudal vertebrae. Concomitantly, there may be injuries to the lumbar, sacral, and/or caudal nerve roots, as well as other types of local damage such as vertebral fractures, lacerations, or degloving of the tail skin. The innervation of this area is complex, involving motor, sensory, sympathetic, and parasympathetic nerves. Trauma in this anatomic location can therefore be associated with significant neurologic dysfunction, especially in the voluntary and involuntary control of urination and defecation, and either temporary or permanent fecal and urinary incontinence can occur. Neurologic dysfunction secondary to tail pull injuries is the most common cause of euthanasia in these patients, although many can recover if given time.
Early tail amputation is often unnecessary and contraindicated in many patients with tail pull injuries, as a significant number can recover tail function. Hitherto, surgical stabilization of sacrococcygeal luxations with pins and wires has been found to have variable results and was generally not recommended. In the initial period following a tail pull injury, it can be impossible to identify the extent, severity, and prognosis of the neurologic trauma involved. Neuropraxia and axonotmesis have a good prognosis, but neurotemesis does not, and often only time tells the difference.
In this retrospective review of medical records (2009-2015) of 15 cats suffering loss of pain perception in the tail secondary to tail avulsion injuries, the outcome of tail reconstruction (following surgical exploration) was evaluated. All of these patients had lost voluntary motor function in the tail and 8/15 had urinary incontinence. Two of the eight patients with urinary incontinence also had absent perianal and perineal reflexes. All surgical patients were severely painful preoperatively. Those patients who had open tail fractures, tail wounds necessitating amputation, caudal nerve root transection identified by surgical exploration, or additional vertebral column injuries, were excluded from the study.
These 15 patients were young (average age 2 years; range, 3 months to 5 years) and mostly male (11/15); four were female. In 10/15 of the cats, the avulsion injury was a sacrocaudal luxation, while in two the luxation was caudo-caudal (Ca1-Ca2). Four of the cats had sacral fractures, and one had lesions at both S2-S3 and S3-Ca1. Cats who underwent primary surgical tail stabilization received serial neurologic examinations, preoperative, postoperative, and follow-up radiological examinations, and follow-up interviews by the investigators with the animals' primary care veterinarians and/or owners.
Description of the surgical procedure is accompanied by excellent photographs as well as radiographs. The surgery was performed one day after admission to the hospital. Initially the nerve roots within the surgical site were inspected. Vertebral stabilization was then performed if total nerve root transection was not observed. The first step in surgical stabilization was to create a small bone tunnel, 1.1 mm diameter at the base of the dorsal spinous process of S2 (occasionally S3) using a K-wire or small drill bit. Next, the luxated vertebrae were repositioned using a pointed fragment forceps. A nonabsorbable 2/0 polypropylene suture was then passed around one of the transverse processes of the luxated sacral or caudal vertebra and through the drilled bone tunnel; the same procedure was also performed on the contralateral side. Fixation was then accomplished by progressively tying the knots one at a time while monitoring to be sure that facet reduction was appropriate, but that knots were not tied so tightly as to cause dorsal angulation. Postoperative radiographs of all 15 patients who underwent stabilization surgery demonstrated good reduction and alignment of caudal vertebrae. All of the patients also experienced a marked reduction in pain scores and were considered to be experiencing low-level pain by only 48 hours postoperatively. Major postoperative complications were not reported for any of the cats; 14/15 had some episodic loss of balance while jumping and landing during the first few weeks following surgery.
Voluntary motor function of the tail and pain perception in the tail were re-established in 11/15 of the cats who underwent primary stabilization surgery; the time period for this recovery was 3-90 days. Five of 8 cats with urinary incontinence recovered normal urinary function within 3-30 days, and three did not recover from urinary incontinence. Four of the patients did not recover voluntary motor function of the tail; all four of these patients also had pre-operative urinary incontinence, and three of these four also did not return to normal urinary continence. Two of the three cats who did not recover from urinary incontinence were euthanized, and one was managed medically.
Previous studies have demonstrated that recovery of voluntary motor function and sensation in the tail can take up to 150 days. Therefore, tail amputation should be avoided until the patient is re-evaluated for recovery of motor function and pain perception in the tail 90-150 days after injury. The authors do recommend tail amputation for those patients diagnosed with neurotmesis on surgical exploration. None of the 15 patients who underwent primary stabilization in this study self-mutilated, even in those with no recovery of tail voluntary motor function. Fourteen of 15 owners whose cats had the stabilization surgery were satisfied with the results, even when there was not complete recovery.
Stabilization surgery of tail avulsion injuries is likely to result in faster diminution of pain than conservative management, because alignment and stabilization of the vertebrae limits continual stretching of nerve roots and the impingement of bone fragments on these nerve roots. Patients in whom conservative management of tail avulsion injuries is applied are reported to have severe pain several weeks post-injury and often require analgesia for at least one month. Moreover, 80% of patients conservatively managed have persistent motor deficits. Conservative / medical therapy of tail pull injuries is most likely to be effective when there is still pain perception at the tail base.
The authors recommend that any cat with a tail avulsion injury that still has urinary continence should be surgically explored to assess the nerve lesions. Amputation of the tail should be performed if there is neurotmesis, and may need to be considered if the animal is self-mutilating or if voluntary tail motor function does not return after a period of time. The prognosis for recovery from urinary incontinence is more guarded regardless of whether surgical or conservative/medical management is chosen. For those animals undergoing medical treatment that experience persistent pain, surgical exploration followed by repair or amputation is a recommended option. A clinical trial comparing primary surgical stabilization to conservative management of tail pull injuries, particularly in the group of cats who still have pain perception in the tail base, would be useful in evaluating both methods of treatment.
